this is actually true provided you are the only person in the room. as humans, we "see" by interpreting the light bouncing off of all of the objects around us. we know the color and size of an object by what wavelength of light is reflected and how much of that light is reflected.

when our eyes are open, we "see" the "particles" of light in exactly one place, and in so doing we determine the existence and position of a certain object. however, light does not always exist as a particle. under natural circumstances, with no observers, light exists as a wave of probability. by this i mean that light normally exists in multiple places simultaneously. the strange thing about this is that the mere act of observing, simply having someone there to "see" the light, changes its properties. Observing light collapses its wave function into a single point with a known position. For those of you who are still skeptical, this was proven via the double-slit test.
Anyway to get to my point, if unobserved light exists not in one place as we thought, but as many waves of probability, then we can say that when you close your eyes and you are alone, the physical world that we as humans casually assume to be the whole picture, loses all definite form.
This is interesting because we as humans interpret the physical world by scanning in a very small range of electro-magnetic waves (light). We base so much of what we call "truth" on the assumption that the visible light spectrum reveals all the universe has to offer. But ask yourself, what if humans evolved to "see" radio waves, or "see" gamma rays. How different would the world look to us? We may never know...

tl:dr, the world does "disappear" when no one is watching, pic related: mfw i first started doing research on the subject

can you press a button on your head that switches your eyes to radio mode and lets your brain paint a picture with whatever you pick up? no? that's a shame. radio telescopes pick up radio waves and provide a visual representation to the user. there's a difference between taking pictures of the radio waves in the cosmos and walking around every single day seeing radio waves with your eyes. or any other frequency of EM radiation for that matter. just because we can use machinery to detect such radiation does not mean we can "see" it.

somebody with a brain stem might enjoy reading that. if it's too difficult for you to comprehend you can just move right alone and laugh at your little pony pictures and thumb up some tits. uneducated twats like you make me embarrassed to be a human being.

i'm going to go out on a limb and assume that you didn't learn quantum mechanics in kindergarten. the idea that observation changes the properties of light is pretty new and took some pretty ridiculous science to prove, pal.